JP3338970B2 - Coating solution for forming transparent conductive film and low-reflection transparent conductive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating solution for forming a transparent conductive film for shielding an electric field, in particular, a coating solution for forming a transparent conductive film which is applied to a glass surface such as a CRT and used for forming a transparent conductive film. And a low-reflection transparent conductive film formed on a glass surface using this coating solution.

[0002]

2. Description of the Related Art As an ink for forming an antistatic film on a surface of a cathode ray tube of a display or a television, an ATO (tin-antimony oxide) sol-gel ink has been put into practical use. A surface resistance value of about 10 ¹¹ Ω / □ is required for countermeasures against static electricity, but this level is a level that ATO can sufficiently cope with.

[0003] In recent years, however, there has been growing interest in humans about the effects of electromagnetic fields generated by CRTs, mainly in Europe, and guidelines have already been established in Sweden and some other countries. Regulations have not been reached in the United States and Japan, but countermeasures are being considered. It is said that the stray magnetic field can be solved by a device, but the response to the electric field is not uniform.

[0004] As a method of shielding the electric field on the CRT surface, there is a method in which an ITO film is deposited on the surface of a CRT cathode-ray tube glass by vapor deposition or sputtering, or a plastic panel is fitted. Have been. This method is satisfactory in terms of performance since the resistance can be sufficiently reduced, but has not yet been put to practical use widely in general because of the high manufacturing cost.

From such a background, a method of forming a conductive film by coating has been studied. In this method, for example, a solution of an organometallic compound is applied to a substrate and then heated and baked to form a conductive film. According to the coating method, there is an advantage that a large area is not required, and a large area and mass production are easy.

Japanese Patent Publication No. 57-138108 discloses alcohols, cellosolves, carbitols, and glycols containing an indium compound, a tin compound and a solvent.

Japanese Patent Publication No. 61-26679 discloses an organic indium compound containing an acetylacetone group, an organic tin compound represented by [Y] ₂ Sn [X] ₂ , and an organic solvent. Ethyl acetate and benzene are disclosed.

Japanese Patent Application Laid-Open No. 4-255768 discloses a coating solution containing indium nitrate, an organotin compound, hexylene glycol, and acetic acid and / or acetic anhydride.

JP-A-57-36714 discloses an organic compound having a coordinating ability comprising an inorganic indium compound, an organic compound having a coordinating ability, a tin compound, a viscous agent such as cellulose, and a solvent. Carboxylic acids,
Carboxylic esters and hydroxy acids are disclosed.

[0010] JP-A-57-212268 discloses a paste composition comprising an indium compound, a tin compound, an organic solvent and a cellulose compound.

JP-B-63-25448 discloses a composition containing an indium compound, a tin compound for adjusting a resistance value, nitrocellulose as a viscosity agent, and cellsorb, carbitol, benzyl acetate, and dimethyl phthalate as a solvent. Have been.

[0012] Also, Japanese Patent Publication No. 2-20706 discloses that
A composition comprising triacetonato indium, tin bisacenalacetonate, a cellulose compound, and high boiling alcohols is disclosed.

JP-B-63-19046 discloses that a monoazo organic compound is added to a paste comprising an indium compound such as indium triacetylacetonate, an organic tin complex such as dimethyltin acetobe, a viscous agent, and an organic solvent. An added composition is disclosed.

[0014]

The coating solution for forming a transparent conductive film is a paste obtained by adding an organic or inorganic conductive fine particle to an organic solvent. The film forming properties, conductivity, transparency, and mechanical strength of the conductive film depend on the type, properties, particle size, amount added, and properties of the organic solvent of the selected conductive fine particles. It can be said that the selection of the combination is a repetition of trial and error because the film characteristics are determined by the interaction with.

Further, since the viscosity of the coating liquid increases with the amount of cellulose contained in the organic solvent, cellulose is added to the coating liquid used for film formation by spin coating, which requires a low viscosity. No. 57-13
No. 8108 and JP-B-61-26679 are preferably used. By using such a composition, a transparent conductive thin film can be formed by a spin coating method, but this composition does not necessarily guarantee sufficiently satisfactory film properties, and there is room for improvement. I have.

Further, when a transparent conductive film is formed on a glass substrate, a problem is that if a coating solution is applied, heated and baked on the substrate, the conductive film is glossy.
There is a problem that light is reflected and the screen is difficult to see. In general, there is a technique of applying a low-reflection overcoat to eliminate gloss, and a coating liquid having a low reflection and high light transmittance, such as a coating liquid (alkyl silicate sol liquid) containing a silicon alkoxide liquid, is known. However, such a coating solution has poor adaptability to a conductive coating solution, and a film obtained by overcoating an alkyl silicate sol solution on a film formed by each of the coating solutions, drying and baking, It is not practical for practical use due to unevenness and uneven streaks.

An object of the present invention is to provide a coating solution for forming a transparent conductive film having a low viscosity and excellent conductivity, and a low-reflection transparent conductive film excellent in light transmittance and mechanical strength by using this solution. Is to do.

[0018]

In order to achieve the above object, a coating liquid for forming a transparent conductive film according to the present invention comprises a coating liquid for forming a transparent conductive film containing an organic indium compound, organic tin and an organic solvent. In the coating solution, the organic indium compound is at least one selected from indium acetylacetonate and indium octylate, and the organic tin is at least one selected from tin acetylacetone and tin octylate. The organic solvent is selected from at least one of an acetylacetone solution in which alkylphenol and / or alkenylphenol is dissolved, and a liquid obtained by diluting an acetylacetone solution in which alkylphenol and / or alkenylphenol is dissolved with alcohol.

The transparent conductive film-forming coating solution according to the present invention is a transparent conductive film-forming coating solution containing hydroxypropylcellulose, wherein hydroxypropylcellulose is a total alkylphenol contained in an organic solvent. And / or 1.0 to 12.5% by weight of the alkenylphenol.

The low-reflection transparent conductive film according to the present invention is a low-reflection transparent conductive film formed by laminating a transparent conductive film and a coating film, wherein the transparent conductive film is used for forming the transparent conductive film. A coating film formed on the substrate by applying a coating liquid, and the coating film is obtained by overcoating the transparent conductive film with a coating liquid containing silicon alkoxide.

[0021]

In the present invention, indium acetylacetonate (AcAcIn) and indium octylate (OctIn) are used as the organic indium, and in the examples, the trade name is Nasemuindium (Metal Acetylacetate).
onate, In 28%, manufactured by Nippon Chemical Industry Co., Ltd., Hope In (In 25%, manufactured by Hope Pharmaceutical Co., Ltd.), bisacetylacetonatodimethyltin (AcAc) as organotin
Sn), tin octylate (OctSn), in the examples, trade name Narsem Tin (manufactured by Nippon Kagaku Sangyo Co., Ltd.), Nikka Octinate (Stannous Octoate, Sn28)
%, Manufactured by Nippon Chemical Industry Co., Ltd.).

As alkylphenols, p-tert-butylphenol, octylphenol, nonylphenol and the like can be used, and as alkenylphenols, 3-pentadecadecylphenol and the like can be used. As alcohols, cyclohexanol and the like can be used in addition to methyl, ethyl, propyl, and butyl alcohol. Of course, the above-mentioned other alcohols may be appropriately added to ethyl alcohol.

The coating solution of the present invention is usually a transparent solution containing the above-mentioned a) indium compound, b) tin compound, c) alkyl and / or alkenyl phenol, d) acetylacetone solution and / or a mixture of acetylacetone and alcohol. It is a clear solution in which 1.0 to 12.5 wt% of alkyl and / or alkenyl phenol is substituted with hydroxypropyl cellulose. Such a solution can be obtained, for example, by stirring these components between room temperature and 150 ° C. for 0.5 to 12 hours. Table 1 shows examples of solution viscosities obtained under the above manufacturing conditions. Table 1
Indicates the wt%. The same applies to the following table.

[0024]

[Table 1]

The coating liquid of the present invention can be formed by spin coating, spray coating, bar coating and blade coating.

The coating liquid of the present invention has satisfactory wettability with a glass substrate and has a moderate boiling point and / or a mixture of a medium boiling point and a low boiling point. However, the volatilization provides the film-forming components with the substrate and the resistance to overcoating (there is no generation of grains, no band-like pattern, or whitening), and leveling occurs due to the residual solvent. Can be obtained.

A) AcAcIn (or OctIn),
b) AcAcSn (or OctSn), c) alkyl and / or alkenyl phenol, d) acetylacetone and / or a mixed solution of acetylacetone and ethyl alcohol, the substrate temperature during the coating operation is 45 to 60 ° C. Set to. If the temperature is lower than 45 ° C., the coating solution exhibits a repelling phenomenon on the substrate. If the temperature exceeds 60 ° C., the evaporation rate is high, the surface tension is large, and the film thickness is not uniform.

When the substrate temperature is set at 45 to 60 ° C.,
AcAcIn (or OctIn) in coating solution + AcAc
When Sn (or OctSn) exceeds 5 wt%, cracks were generated in the film obtained by drying and firing without overcoating the alkyl silicate sol solution. On the other hand, when the content is less than 5 wt%, repelling occurs during the coating operation. However, the film obtained with the 5 wt% coating solution is
No inconvenience such as repelling or cracking, surface resistance 6KΩ
/ □ is indicated.

AcAcIn (or OctI) in the coating solution
n) + AcAcSn (or OctSn) is applied on a substrate set at 45-60 ° C. with a coating solution of 5 wt% or more, and after several minutes, a coating solution containing silicon aldoxide is overcoated, and then dried, The film obtained by firing was excellent in light transmittance and mechanical speed without inconvenience such as cracks.

This is probably because the overcoat layer absorbs the shrinkage of the conductive layer due to the firing. Thus, the first conductive layer is formed as a film having good conductivity because of a large content of In and Sn.

In the above coating liquid of the present invention, 1.0 to 12.5 wt% of alkyl and / or alkenyl phenol
% Can be uniformly applied when the substrate temperature during the coating operation is between room temperature and 60 ° C. It was found that when the replacement amount of hydroxypropyl cellulose was less than 1.0 wt%, a phenomenon of repelling occurred at the time of coating, and when the replacement amount exceeded 12.5%, inconvenience of uneven streaks occurred in the fired film.

FIG. 1 shows that AcAcIn + AcAcSn = 1.
5 wt% (In / Sn = 92/8), para-tert-butylphenol + hydroxypropylcellulose = 1
A coating solution composed of 5 wt% (phenol / cellulose = 95/5) and 70 wt% of acetylacetone was prepared, and diluted with ethyl alcohol to obtain AcAcIn +.
AcAcSn was 12.5 wt%, 8 wt%, 5 wt%, and 2.5 wt%, and the sheet resistance of each film obtained by spin-coating, drying, and firing was shown.
All of the films were excellent in light transmittance and mechanical strength without any inconvenience such as cracks, and had very small in-plane variations.

FIG. 2 shows that OctIn instead of AcAcIn
Was replaced with OctSn in place of AcAcSn.
The results obtained by the same method as in FIG. 1 are shown. As is clear from FIG. 2, when the combination of OctIn and OctSn is used, the surface resistance is higher than that of the combination of AcAcIn and AcAcSn. Therefore, AcAc
In any combination of In, AcAcSn and OctIn, OctSn, it is considered that the surface resistance value falls between the characteristics shown in FIGS. The surface resistance of the two layers obtained by applying the coating liquid to a film obtained by forming a film using a coating liquid containing no hydroxypropylcellulose, drying, and baking is similar to that having the same surface resistance. Conceivable.

[0034]

The present invention will be described in detail with reference to the following examples.

The coating solution containing silicon alkoxide used for the overcoat was prepared as follows.
That is, 1 gr of 5% hydrochloric acid is added to 5 gr of ethyl silicate 40 (manufactured by Tama Chemical Co., Ltd.) and shaken well. After cooling, 9 gr of water was added and diluted with good stirring, and 110 gr of ethyl alcohol was added to prepare a 4 wt% solution.

(Examples 1 to 3) In a three-necked flask equipped with a stirring rod, a thermometer and a reflux condenser, 150 gr of acetylacetone and 25 gr of tert-butylphenol were added, and the mixture was heated at 120 to 135 ° C for 0.5 hour. Dissolved with stirring. Then 23 gr of AcAcIn and 2 gr of A
cAcSn was added and dissolved at the same temperature for 3 hours. 1μ when cold
Then, the mixture was filtered using a filter paper of m to prepare a coating solution for forming a transparent conductive film.

A half of the obtained coating solution was sampled and used as a sample of Example 1. The other half was diluted with ethanol to obtain AcAcIn + AcAcSn of 8 wt% (Example 2) and 5 wt% (Example 3). Coating solution. 150mm ×
A 200 mm × 9 mm blue glass substrate was placed in a 50 ° C. hot air drying oven for 20 minutes and heated, then set on a spinner, and 10 g of the coating solution was applied at a rotation speed of 150 rpm for 2 minutes.
Coating for 1 minute, and then 10 gr of a 4 wt% alkyl silicate sol solution was applied for 1 minute. 1 in a hot air drying oven at 120 ° C
After drying for 0 minutes, the mixture was placed in a firing furnace, heated from room temperature to 450 ° C. over 1 hour, and fired for 30 minutes after reaching 450 ° C. The properties of the film obtained at 200 ° C. or lower are as shown in Table 2.

[0038]

[Table 2] Blue glass substrate LT 85.9% H 0.0%

(Examples 4 to 6) Instead of AcAcSn, O
Table 3 shows the results obtained by using exactly the same material configuration and manufacturing method as in Examples 1 to 3 except that ctSn was used.

[0040]

[Table 3] Blue glass substrate LT 85.9% H 0.0%

(Examples 7 to 9) Instead of AcAcIn, O
Table 4 shows the results obtained by using exactly the same material configuration and manufacturing method as in Examples 1 to 3 except that ctIn was used.

[0042]

[Table 4] Blue glass substrate LT 85.9% H 0.0%

(Examples 10 to 12) Table 5 shows the results obtained by using exactly the same material constitution and manufacturing method as in Examples 1 to 3 except that OctIn was used instead of AcAcIn and OctSn was used instead of AcAcSn. .

[0044]

[Table 5] Blue glass substrate LT 85.9% H 0.0%

(Examples 13 to 22) In a three-necked flask equipped with a stir bar, a thermometer and a reflux condenser, acetylacetone and paratertiary butylphenol were placed in a three-necked flask at 120 to 13 minutes.
The mixture was dissolved with stirring at 5 ° C. for 0.5 hour. Next, a calculated amount of hydroxypropylcellulose was gradually added and dissolved at the same temperature for 1 hour. After adding 23 gr of AcAcIn (or OctIn) and 2 gr of AcAcSn (or OctSn) and stirring and dissolving for 3 hours, the solution was filtered using a 1 μm filter paper to prepare a coating solution for forming a transparent conductive film. The properties of a film obtained by spin-coating the obtained coating solution in exactly the same manner as in Examples 1 to 3 except that the substrate temperature is room temperature [20 ° C.], and drying and firing as it is without overcoating Are shown in Tables 6 and 7.

[0046]

[Table 6]

[0047]

[Table 7]

(Examples 23 to 26) In a three-necked flask equipped with a stirring rod, a thermometer and a reflux condenser, 150 gr of acetylacetone and 25 [1-x] gr, where x is the substitution rate of hydroxypropylcellulose At 0.125,
0.08, 0.05 and 0.10 para-tert-butylphenol were dissolved with stirring at 120-135 ° C for 0.5 hour. Next, a calculated amount of hydroxypropylcellulose was gradually added and dissolved at the same temperature for 1 hour. Ac
After adding 23 gr of AcIn and 2 gr of AcAc and stirring and dissolving for 3 hours, the solution was filtered using a 1 μm filter paper to obtain Example 2.
The coating liquids for forming a transparent conductive film of Nos. 3 to 26 were prepared. The coating solution obtained was spin-coated and overcoated in exactly the same manner as in Examples 1 to 3 except that the substrate temperature was room temperature [20 ° C.], and dried and fired as it was. It was shown to.

[0049]

[Table 8] Blue glass substrate LT 85.9% H 0.0%

[0050]

As described above, the coating solution for forming a transparent conductive film of the present invention has excellent transparency, low viscosity, and good wettability to a glass substrate. By using the coating method, a uniform transparent conductive thin film can be formed on a glass substrate, and because it is well compatible with commonly used coating liquids containing silicon alkoxide, overcoating the surface A transparent conductive film having excellent mechanical strength can be formed by reflection, and excellent effects in electric field shielding such as CRT and antistatic can be obtained.

In the present invention, it should be noted that AcAcIn [or OctIn] and AcAc in the coating solution are different from each other.
When the total amount of Sn [or OctSn] is 5% by weight, a conductive film having low resistance and free from inconvenience of cracking and repelling was obtained. Therefore, by specifying the compounding amount of the component, it is not necessary to add a viscous agent, and it is possible to form a transparent conductive film having extremely low viscosity and thus excellent spreadability by spin coating.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the addition amount of AcAcIn and AcAcSn and the surface resistance of a film.

FIG. 2 is a diagram showing the relationship between the added amount of OctIn and OctSn and the surface resistance of a film.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hirotoshi Koizumi 7-9-4 Nishigotanda, Shinagawa-ku, Tokyo Tohoku Kako Co., Ltd. (56) References JP-A-61-9471 (JP, A) 57-199105 (JP, A) JP-B 63-19044 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 13/00 H01B 5/14 C09D 5/24

Claims (3)

(57) [Claims] 1. A coating liquid for forming a transparent conductive film comprising an organic indium compound, an organic tin and an organic solvent, wherein the organic indium compound is selected from at least one of acetylacetone indium and indium octylate. The organic tin is at least one selected from tin acetylacetone and tin octylate, and the organic solvent is an acetylacetone solution in which alkylphenol and / or alkenylphenol is dissolved, alkylphenol and / or A coating solution for forming a transparent conductive film, wherein at least one of a solution obtained by diluting an acetylacetone solution in which alkenylphenol is dissolved with alcohol is selected. 2. A coating liquid for forming a transparent conductive film containing hydroxypropylcellulose, wherein hydroxypropylcellulose is present in an amount of 1.0 to 12 of the total amount of alkylphenol and / or alkenylphenol contained in the organic solvent. 2. The coating liquid for forming a transparent conductive film according to claim 1, wherein an equivalent amount of 0.5% by weight is substituted. 3. A low-reflection transparent conductive film comprising a laminate of a transparent conductive film and a coating film, wherein the transparent conductive film is formed by applying the coating liquid for forming a transparent conductive film according to claim 1 or 2. A low-reflection transparent conductive film, wherein the coating film is obtained by overcoating the transparent conductive film with a coating liquid containing silicon alkoxide.